Shutter locking device for cameras



June 30, 1931. E. c. THOMPSON l 1,812,181

SHUTTER LOCKING DEVICE FOR CAMERAS Filed Feb. 23. 1928 mlhmm Patented June 30, 1931 PATENT OFFICE EU.GrEllI'P-lV C. THOMPSON, OF LOS ANGELFS,'CALIFORNIA SHUTTER LOCKING DEVICE FOR CAMERAS Application led February 23, 1928.'

The object of my invention is to provide a device for the prevention of double exposure in roll film cameras of the conventional and well known type, which device may be attached to any ordinary camera adapted to receive roll films without the modification of any mechanism of the camera or shutter.

1t may be pointed out that in folding roll film cameras available space for the attachio ment of any additional mechanism is extremely scarce, and those skilled iii the art have found it difficult to apply any attachment whatever to folding roll-film cameras in such manner that the attached device would in no way interfere with the folding or picture taking functions of the camera. In rolling up the film on the winning spool the diameter of the roll constantly increases, resulting in a varying number' of turns of the 2o Winding key being required to bring up a new section of film to exposure position. A ccordingly, allowance must be made for this. The present invention has for one of its novel features means for insuring the shutter actuating mechanism being locked at theproper time, regardless of whether the winding key be turned two and a half or three and a half revolutions, and the like. In the present invention I provide novel mechanism by which the turning of the winding key for rolling up the film controls the actuation of the shutter, in the sense that it locks or unlocks the shutter actuating mechanism.

In the drawings, Fig. 1 is a front elevation of the essential parts of a roll film camera, showing my invention applied thereto.

Fig. 2 is a fragmentary view, part-ly in side elevation, partly in vertical section, of the cam mechanism, taken on line 2-2 of Fig. 1. Fig. 3 is a transverse vertical sectional view of the winding spool mechanism and associated parts of applicants device relative thereto, taken on lines 3-3 of Fig. 2.

Fig. 4 is a fragmentary view showing ani other position of the cam member.

Fig. 'is a horizontal sectional view of the film locking device taken on lines 5--5 of Fig. 6.

Fig. 6. is a vertical sectional view taken on the indirect line 6 6 of Fig. 5.

Serial No. 256,111.

Fig. 7 is a view similar to Fig. 6, but showing the locking mechanism in another position.

Fig. 8 is a view similar to Fig. 7, showing still another locking position.

Fig. 9 is a. view similar to Fig. 8, showing another position of the locking device.

Referring to the drawings, a cam 3 fits loosely over the flanged end of the winding key it, shown in section in Fig. 3, but being 6C well known to those skilled in the art, and not claimed as a part of my invention, is not described herein. This cam is held in place by a thin metal plate 5 (Fig. 3), perforated for the passage of the fiange of the winding i key 4. An ordinary cable release 6 (Bowden wire) has its linger knobs removed, and its tube-like end 7 screwed into the wall of the film chamber adjacent the side wall of the camera. This cable release 6 being well 70 known to those convei'sant with the art will not be specifically described. The tubeeend 7, of the cable release carries the short shaft 8, attached to the cable of the release, which is held against the cam 3 in its travel by the 75 spring with which these releases are normally equipped. The other `end 9 of this release is screwed into the cover plate 16.

A U-shaped plate 10 is attached to the shutter holding plate 11 of the camera 12 by 80 screws, not-shown. The side walls of this plate are shown at 14, Fig. 5, and the bedplate 15 of the plate 10 is partly cut away, as shown at 15. This bed plate 15 has a cover 16, with its ends bent down, as shown at 16 and 16". Sliding on the bed plate 15 is a plate 17, called the locking plate, with a rectangular opening 18 (Fig. and a narrow extension thereof 18. T his locking plate 17 has a. nib 19 turned down, adapted to drop 90 into the aperture 26 in bed plate 15. The bed plate 15 an-d its cover 16 are each respectively perforated with cross-shaped openings 21 and 22, the shape of which will be more clearly apparent in Fig. The cover plate 16 has an angularly projecting lip 23 for the attachment of the spring 211, the other end of the spring being attached to the plate 17 at 25. This cover plate 16 also has a threaded perforation 26 into Which is with the film roll for actuating the plunger.

3. In a camera adapted to receive roll films, the combination with a film spool-winding key and shutter actuating mechanism, of means for placing said shutter actuating mechanism in operative or inoperative position, comprising a horizontally slidable plate having an opening therein, a vertically movable locking member normally positioned in said opening, operative connection between the locking member and the camera shutter, and means for locking the vertically moving member with said horizontally slidable plate in a predetermined position upon actuation y of the camera shutter.

4. In a camera adapted to receive roll films, the combination with a film spool-winding key and shutter actuating mechanism, of means for placing said shutter actuating mechanism in operative or inoperative position, comprising a horizontally slidable plate having an opening therein, a vertically movable locking member normally positioned in said opening, operative connection between the locking member and the camera. shutter, means for locking the vertically moving member with said horizontally slidable plate in a predetermined position upon actuation of the camera shutter, and additional means for releasing the said locking member.

5. In a camera adapted to receive roll films, the combination with a film spoolwinding key and shutter actuating mechanism, of means for placing said shutter actuating mechanism in operative or inoperative position, comprising a horizontally slidable plate having an opening therein, a vertically movable locking member positioned in said opening, operative connection between the locking member and the camera shutter, means for locking the vertically moving member with said horizontally slidable plate in a predetermined position, upon actuation of the camera shutter, and additional means for releasing the said locking member, said ladditional means including a plunger adapted to actuate the slidable plate and a cam operatively associated with the film roll for actuating the plunger.

In testimony whereof I aix my signature.

EUGENE C. THOMPSON. 

